Avoid default SkFont in tests

Change-Id: I003aa8fcc4de2f6a4e34663a26ebc21d207dcd94
Bug: b/305780908
diff --git a/libs/hwui/tests/common/TestUtils.h b/libs/hwui/tests/common/TestUtils.h
index ffc664c..0ede902 100644
--- a/libs/hwui/tests/common/TestUtils.h
+++ b/libs/hwui/tests/common/TestUtils.h
@@ -30,6 +30,7 @@
 
 #include <SkBitmap.h>
 #include <SkColor.h>
+#include <SkFont.h>
 #include <SkImageInfo.h>
 #include <SkRefCnt.h>
 
@@ -353,6 +354,8 @@
 
     static CallCounts& countsForFunctor(int functor) { return sMockFunctorCounts[functor]; }
 
+    static SkFont defaultFont();
+
 private:
     static std::unordered_map<int, CallCounts> sMockFunctorCounts;